BIO-AGRICULTURAL  ^LIBRARY 
UNIVERSITY  OF  CALIFORNIA 
RIVERSIDE,  CALIFORNIA  92502 


AGR 

RiVtRSIDE,  CALIFORNIA 


BOTANY 


BY 

HERBERT  MAULE  RICHARDS 


PROFESSOR    OF    BOTANY 
COLUMBIA    UNIVERSITY 


JVcw  York 

THE  COLUMBIA  UNIVERSITY  PRESS 
1908 


BOTANY 


A  LECTURE  DELIVERED  AT  COLUMBIA  UNIVERSITY 

IN  THE  SERIES  ON  SCIENCE,  PHILOSOPHY  AND  ART 

DECEMBER  4,  1907 


BOTANY 


BY 

HERBERT  MAULE  RICHARDS 


PROFESSOR   OF    BOTANY 
COLUMBIA   UNIVERSITY 


THE  COLUMBIA  UNIVERSITY  PRESS 
1908 


COPYRIGHT,  1908, 
By  THE  COLUMBIA  UNIVERSITY  PRESS. 

Set  up,  and  published  February,  1808. 


BOTANY 


WHAT  is  the  content  and  scope  of  the  science  of  botany? 
Popular  opinion  will  answer  somewhat  easily:  Botany 
consists  in  the  gathering  of  plants,  and  the  dismembering 
of  them,  in  connection  with  the  use  of  a  complicated  ter- 
minology. That  is  the  beginning  and  end  of  botany  as  it 
is  understood  by  the  majority;  there  is  nothing  more  to 
be  said.  In  consequence,  the  employment  of  the  botanist 
seems  so  trivial,  so  very  remote  from  important  human 
interests  that  no  second  thought  is  given  to  it.  The  con- 
ception formed  in  ignorance  is  continued  in  ignorance. 
Even  the  zoologist  is  at  an  advantage,  for  the  public  is 
finally  forced  to  admit  that  it  does  not  know  what  he  is 
about,  while  it  understands  the  botanist  very  well.  He  is 
quite  hopeless,  for,  while  flowers  may  be  pretty  things  to 
pick,  they  should  not  be  pulled  to  pieces,  and  if  he  does  not 
happen  to  be  interested  in  dissecting  flowers  he  is  not  a 
botanist  but  simply  a  fraud. 

Far  from  being  remote,  the  study  of  plants  comes  very 
close  to  human  interests.  One  has  but  to  stop  to  think 
that  plants  are  the  great  energy  source  for  man  himself 
and  the  animals  upon  which  his  well-being  depends,  to 
recognize  that  a  careful  study  of  their  manner  of  life,  the 
conditions  which  favor  or  hinder  their  growth  is  of  the 
very  first  importance.  Besides  this,  human  curiosity  de- 
mands that  plants  be  investigated,  if  for  no  other  reason 
than  that  they  must  be  made  to  yield  answers  to  the  per- 

5 


petual  questions  that  man  is  asking  regarding  the  world 
about  him. 

Under  botany  we  have  to  consider  all  the  questions  as 
to  the  form,  the  functions,  the  classification  and  the  dis- 
tribution of  those  organisms  that  are  called  plants.  Along 
what  lines  this  study  is  prosecuted,  how  it  is  related  to 
other  fields  of  intellectual  activity,  and  some  specific  in- 
stances of  its  problems  and  the  manner  in  which  they 
may  be  solved  is  what  I  shall  attempt  to  tell  you. 

It  would  be  out  of  place  in  a  talk  like  this  to  devote  too 
much  time  to  a  consideration  of  the  historical  side  of  the 
subject,  and  therefore  only  a  few  of  the  important  move- 
ments can  be  pointed  out.  Any  folk  which  had  so  far 
emerged  from  the  stage  of  savagery  as  to  stop  to  notice 
the  world  about  it  would  perforce  pay  some  attention  to 
plants.  A  discrimination  of  the  medicinal  uses  of  plants  is 
often  noticeable  even  in  primitive  peoples,  and  with  such 
observation  goes  also  the  discrimination  of  difference  in 
form,  the  prototype  of  morphological  research.  I  have 
seen  a  Malay  coolie  who  could  distinguish  seven  forms  of 
tropical  oaks  where  the  botanist  recognizes  only  four,  an 
evidence  that  sharp  observation  is  not  confined  to  the 
highly  developed  races. 

In  our  own  civilization,  we  can  trace  back  the  history 
of  botany  to  Aristotle,  who  affords  us  some  record  of  the 
plant  forms  known  at  his  time,  though  the  influence  which 
his  philosophy  wielded,  even  down  to  the  middle  of  the  last 
century,  was  of  vastly  greater  importance  than  any  con- 
tribution which  he  made  to  botany  itself.  Theophrastus 
gave  a  fuller  account  of  plants,  and  later  came  the  inquir- 
ing and  ever  curious  Pliny.  Dioscorides,  however,  in  the 
first  or  second  century  of  our  era,  was  one  of  the  first  to 
investigate  plants  with  any  attempt  at  thoroughness  even 
from  the  standpoint  of  the  knowledge  of  the  time.  As  is 
shown  especially  by  Dioscorides'  work,  the  study  of 

6 


plants  was  largely  from  their  use  as  drugs,  and  they  were 
described  simply  to  facilitate  their  recognition.  Any  real 
knowledge  of  them  was  naturally  meager,  and  false  ideas 
that  clung  for  a  long  time,  some  until  comparatively  re- 
cently, prevented  any  proper  conception  of  form  and 
function. 

As  would  be  expected  the  contributions  become  of  less 
and  less  value  as  we  approach  the  middle  ages,  the  botani- 
cal writings  of  which  time  were  full  of  the  wildest  fantasy 
and  superstition.  The  efforts  of  this  period  need  not  ar- 
rest our  attention. 

In  the  sixteenth  century  in  northern  Europe,  particularly 
Germany,  there  was  a  movement  towards  the  real  study 
of  plants  from  the  plants  themselves  as  evidenced  by  the 
works  of  the  herbalists,  but  no  attempt  at  classification 
was  made.  Here  there  was  an  attempt  at  the  enumera- 
tion and  illustration  of  plants  from  living  specimens,  and 
confused  and  empirical  as  this  work  was,  it  was  actuated 
by  an  honest  endeavor  to  record,  as  accurately  as  possible, 
actual  forms,  and  not  fanciful  abstractions  which  never 
did  and  never  could  have  existed.  All  the  descriptions 
were  detached  from  one  another  and  little  or  no  attempt 
was  made  at  classification,  though  by  the  repeated  study 
of  many  similar  forms  the  idea  of  natural  relationship  be- 
gan to  dawn  in  a  vague  way.  The  actual  purpose  of  all 
this  plant  study  was  the  recording  of  the  officinal  plants, 
for  special  knowledge  of  plants  was  still  confined  to  their 
uses  in  medicine. 

While  this  movement  was  advancing  in  northern  Eu- 
rope, a  mainly  artificial  system  of  classification  was  devel- 
oping in  Italy  and  found  its  culmination  in  the  work  of 
Caesalpino,  who  strongly  influenced  the  progress  of  bot- 
any, even  after  his  own  time  and  into  the  middle  of  the 
eighteenth  century.  Great  as  was  the  advance  he  made, 
it  would  have  been  far  greater  had  it  been  given  him  to 

7 


break  away  from  the  scholastic  philosophy  which  hampered 
him.  We  find  a  curious  mixture  of  a  modern  spirit  of 
inductive  natural  science  and  Aristotelian  methods  of 
thought.  The  latter  triumphed  in  the  main,  and  the  result 
was  a  formal  classification  built  on  idealistic  abstractions 
that  is  wholly  fallacious  from  our  standpoint  of  to-day. 

Emerging  from  such  conditions  we  find  Linnaeus — the 
bicentenary  of  whose  birth  was  celebrated  last  year — and 
though  he  too  was  much  influenced  by  the  earlier  writers, 
to  him  belongs  the  credit  of  the  emphasis  on  the  fact  that 
some  natural  system  of  the  classification  of  plants  must 
exist  even  though  he  could  not  determine  it.  Linnaeus  is 
popularly  termed  the  father  of  botany  and  of  zoology  as 
well,  and  in  many  senses  there  is  reason  for  it.  He  was  a 
born  classifier  and  brought  considerable  order  out  of  im- 
mense chaos,  but  still  his  classification  was  artificial,  and 
only  to  a  very  limited  degree  recognized  the  natural  rela- 
tionships of  plant  forms.  Linnaeus,  however,  was  wise 
enough  to  recognize  its  artificiality. 

From  Linnaeus  the  advance  was  more  rapid,  and,  while 
most  of  the  study  in  plants  centered  on  the  work  of  classi- 
fication, there  were  unmistakable  signs  of  other  interests. 
The  ideas  of  the  classifier  were  still  hampered  by  the 
dogma  of  the  constancy  of  species,  which  continually 
clashed  with  the  insistent  and  undeniable  evidences  of  the 
genetic  relationships  of  organic  forms.  Despite  the  move- 
ment in  favor  of  the  idea  of  the  development  of  species 
from  previously  existing  forms,  despite  the  views  ad- 
vanced by  Lamarck  and  others  at  about  that  time,  despite, 
indeed,  the  more  strictly  botanical  investigations  in  the 
morphological  field  which  were  brought  forward  during  the 
first  half  of  the  nineteenth  century:  despite  all  these  things, 
the  botanist  was  unable  to  break  away  from  the  concept  of 
groups  of  plants  as  abstract  ideas.  It  was  not  until  1859 
that  the  publication  of  Darwin's  "Origin  of  Species"  drove 

8 


biologists  to  a  different  point  of  view.  Then  the  rational 
idea  of  the  evolution  of  organic  forms  explained  in  a 
similar  rational  fashion  the  observed  genetic  relationships 
of  groups  of  plants.  No  longer  did  the  classifier  hesi- 
tatingly admit  the  possibility  of  the  evolution  of  species 
and  deny  that  of  genera  and  higher  groups,  no  longer  did 
he  maintain  his  artificial  groups,  which  had  no  more  rela- 
tion to  each  other  than  successive  throws  of  dice,  but  he 
admitted  the  whole  great  scheme  implied  by  the  evolution 
of  organic  forms  from  pre-existing  types. 

Naturally,  it  is  difficult  to  point  out  at  just  what  time 
the  modern  trend  of  botanical  work  found  its  origin,  but 
one  can  say,  in  a  general  way,  that  it  was  about  the  middle 
of  the  nineteenth  century,  although  of  the  two  criteria  of 
progress  to  which  I  shall  refer,  one  dates  about  a  decade 
before,  the  other  about  a  decade  after  that  time.  The 
establishment  by  the  botanist  Schleiden  in  1838,  and  by 
the  zoologist  Schwann  in  1839,  of  the  real  nature  of  the 
cell,  and  the  acceptance  of  what  may  be  termed  the  cell 
doctrine,  at  once  made  possible  the  development  of  the 
study  of  form  and  structure,  both  as  to  adult  and  as  to 
embryonic  organs.  With  improved  optical  apparatus 
and  with  improved  technical  methods,  many  able  students 
added  a  vast  number  of  demonstrated  facts  to  the  general 
store  of  knowledge;  in  fact,  for  a  time  the  additions  to 
morphological  information  very  much  outran  the  develop- 
ment of  the  physiological  side,  though  the  latter  had  had 
a  rational  beginning  at  a  prior  date.  The  morphological 
development  depended  in  the  first  instance  upon  the  un- 
derstanding that  the  cell  with  its  living  protoplast,  and 
usually  with  a  wall,  constituted  a  not  further  divisible 
morphological  unit  of  living  organisms;  that  every  cell 
must  have  arisen  from  a  pre-existing  one ;  and  finally,  that 
all  but  the  lower  organisms  are  composed  of  thous- 
ands of  these  cells  differentiated  into  distinct  tissues.  One 

9 


of  the  most  important  figures  in  this  advance  of  botany 
from  Schleiden's  time  was  Naegeli,  who  brought  to  bear  a 
powerful  intellect  on  many  of  the  fundamental  concepts 
both  of  morphology  and  physiology.  Of  the  many  ques- 
tions dealt  with  by  him,  that  of  the  ultimate  structure  of 
organized  substance  was  perhaps  the  most  far-reaching; 
and  today,  despite  its  limitations,  his  Micellar  Hypothe- 
sis, is  the  most  stimulating  of  any  of  the  theories  which 
have  been  developed  regarding  this  subject. 

The  other  milestone  of  progress  was  Darwin's  "Origin 
of  Species"  already  referred  to.  Entirely  aside  from  the 
particular  question  involved  in  that  work,  its  importance 
lies  in  the  fact  that  it  fought  the  battle  and  won  the  victory 
for  the  inductive  method  of  reasoning  as  applied  to  bi- 
ological science.  Previous  to  the  awakening  of  botany, 
due  to  these  and  related  causes,  a  botanist  usually  covered 
the  whole  field  of  his  science  and  had  the  right  to  consider 
himself  a  specialist  in  all  branches  of  botany.  The  rapid 
accumulation  of  facts  soon  demanded,  however,  a  segre- 
gation of  different  lines  of  work.  Thus  arose  the  divisions 
of  botanical  activity,  which,  for  our  purposes,  may  be 
classed  under  three  heads.  First,  the  taxonomic,  or  as 
more  commonly  called  the  systematic  side,  which  has  to  do 
with  the  classification,  mainly  as  established  by  gross 
morphology.  Second,  the  morphological  field  which  con- 
cerns itself  with  the  outward  and  inward  form  and  struc- 
ture and  the  development  thereof,  which  may  or  may  not 
have  direct  relation  with  taxonomic  work.  Third,  there 
is  the  domain  of  physiology  which  treats  of  function.  As 
Professor  Wilson  has  pointed  out,  there  are  really  but  two 
divisions  of  biological  work,  the  morphological  and  the 
physiological,  so  that  the  separation  of  taxonomy  which 
really  belongs  in  the  first  division  is  rather  artificial.  The 
separation  however  is  necessary  for  many  reasons,  among 
which  are  the  fact  that  the  temper  of  mind  and  the 

10 


methods  of  the  workers  in  the  two  divisions  are  quite  dif- 
ferent. 

It  is  perhaps  the  tendency  of  the  time,  at  least  in  many 
quarters,  to  underestimate  the  value  of  taxonomic  research 
and  this  is  to  be  regretted  since  in  classification  we  have 
the  foundations  of  other  branches  of  work.  Entirely  aside 
from  the  philosophical  value  of  a  well  ordered  classifica- 
tion, it  is  an  absolute  necessity  for  a  starting  point  of 
morphology  and  physiology  to  have  the  different  species 
of  plants  recorded  in  recognizable  form,  and,  in  conse- 
quence, to  have  a  classification.  It  would  undoubtedly  be 
a  great  advantage  could  organisms  be  classified  as  are 
chemical  compounds  or  could  be  located  as  the  astronom- 
ers locate  the  stars  and  in  the  same  definite  and  precise  man- 
ner. Such  is  hardly  possible  when  we  reflect  that  the 
question  of  the  identity  of  an  organism  must,  even  under 
favorable  conditions,  be  somewhat  a  matter  of  opinion  as 
well  as  of  demonstrated  fact.  Despite  such  limitations 
of  taxonomy,  in  most  of  the  really  important  questions 
opinion  is  fairly  universal,  so  that  our  classification  is  not 
developed  simply  at  the  whim  of  any  one  investigator. 
Taxonomy,  however,  as  soon  as  it  is  considered  an  end  in 
itself  sinks  at  once  to  the  level  of  mere  cataloguing  or, 
worse  still,  loses  itself  in  the  mazes  of  nomenclatorial  con- 
troversy. It  must  be  considered  in  its  relation  to  the  prob- 
lems of  plant  distribution,  of  the  evolution  of  new  forms, 
of  its  philosophical  intent,  if  it  is  to  retain  its  vitality. 

I  have  spoken  of  artificial  classifications  in  connection 
with  the  work  of  earlier  botanists.  How  then  does  the 
natural  classification  as  understood  today  differ?  Pri- 
marily, it  differs  in  the  admission  of  genetic  relationship 
of  forms,  a  thing  not  conceived  of  by  older  writers.  A 
natural  classification  implies  higher  and  lower  forms,  con- 
nected by  intermediate  ones  in  all  stages  of  differentia- 
tion. However,  it  does  not  imply  that  all  these  forms  exist 

11 


today,  nor  does  it  imply  that  they  developed  in  a  single 
continuous  series  from  the  lowest  to  the  highest.  We  have 
no  particular  right  to  suppose  that  all  plants  can  be  traced 
back  to  a  single  ancestor,  indeed  the  evidence  is  against  it. 
There  is  no  reason  why  several  phyla,  or  lines  of  ascent, 
may  not  have  originated,  perhaps  simultaneously,  from 
the  most  primitive  form  of  living  protoplasm.  The  story 
of  the  lower  aquatic  forms  certainly  indicates  this  possi- 
bility. Of  these  lower  phyla  some  stopped  short,  some 
went  on,  which  ones  is  a  matter  to  be  definitely  settled.  A 
good  instance,  though  a  somewhat  special  one,  to  illustrate 
the  fallacy  of  the  assumption  of  a  single  line  of  relation- 
ship, is  found  among  the  fungi,  the  chlorophylless  lower 
forms.  Many  ingenious  authors  have  attempted  to  unite 
them  in  a  single  continuous  series,  when  every  evidence 
we  now  have  points  to  their  having  originated  at  several 
places  from  the  green  plants.  Who,  indeed,  would  care 
to  deny  that  new  phyla  might  be  originating  today?  Any 
concept  of  evolution  demands  such  a  possibility;  organ- 
isms are  more  plastic  than  the  average  person  conceives, 
even  in  this  age. 

The  object  of  a  natural  classification  is  to  consider  all 
the  many  plant  forms,  to  determine  by  such  marks  of 
genetic  relationship  as  we  can  discover  their  place  in  the 
series,  where  they  have  departed  from  the  main  stem  and 
in  how  far  they  may  have  had  a  line  of  development  of 
their  own.  Despite  what  I  have  said  about  the  lower 
phyla,  it  is  not  improbable  that  the  higher  plants  can  be 
traced  back  to  some  single  source,  not  that  it  is  to  be  be- 
lieved for  a  moment  that  this  ancestor  exists  today.  Liv- 
ing ferns  or  mosses  are  no  more  to  be  considered  the  direct 
ancestors  of  the  flowering  plants  than  are  monkeys  to 
be  considered  the  direct  ancestors  of  man. 

The  establishment  of  our  classification  today  might  be 
compared  to  the  putting  together  of  a  puzzle  map  some 

12 


parts  of  which  are  lost;  we  can  determine  how  many  of 
the  parts  fit  together,  and,  by  analogy,  can  tell  something 
of  the  missing  ones.  The  whole  method  depends  on  the 
admission  of  genetic  relationship,  a  concept  that  is  built 
up  partly  by  the  study  of  adult  structure,  partly  by  the 
story  of  the  developmental  stages,  partly,  though  in  bot- 
any less  than  in  zoology,  by  the  evidence  of  paleontology, 
but  more  vividly  than  in  any  other  way  by  the  actual 
behavior  of  certain  plants  in  the  matter  of  giving  rise  to 
new  forms.  This  last  consideration  is  of  such  great  im- 
portance that  we  shall  come  back  to  it  later. 

One  type  of  morphological  investigation  has  to  do  with 
the  study  of  life  histories  of  plants,— the  whole  life  story 
from  egg  to  egg  again — and  here  we  find  the  morpholo- 
gist  in  close  relation  with  the  systematist,  for  upon  the 
results  of  such  researches  must  largely  depend  the  under- 
standing of  the  relationships  of  the  great  groups.  The 
morphologist  who  devotes  his  time  to  the  study  of  life  his- 
tories is  engaged  in  the  work  of  tracing  the  race  history 
of  plants  from  the  comparison  of  the  individual  develop- 
ment of  more  or  less  nearly  related  forms.  Thus  the 
homologies  which  have  been  traced  among  the  flowering 
plants  and  their  nearest  allies  among  the  ferns  and  other 
forms  indicate  to  us  the  probable  race  history  of  these 
groups.  It  is  true  that  the  beginning  of  this  work  dates 
back  some  decades,  but  it  is  still,  to  a  large  extent,  an  open 
field,  and  numerous  investigators  are  actively  prosecuting 
research  along  these  lines.  For  example,  the  alternation 
of  a  sexual  and  nonsexual  generation  of  plants  which  has 
long  been  known  as  characteristic  of  the  life  histories  of 
higher  forms  has  recently  been  established  among  the 
lower  groups,  and  thus  a  much  clearer  view  of  the  whole 
series  of  the  plant  kingdom  is  being  obtained. 

Somewhat  separated,  and  to  a  large  extent  needlessly 
so,  is  the  work  of  the  plant  anatomist  and  histologist. 

13 


Formerly  pursued  from  the  standpoint  of  the  mere  topo- 
graphical relation  of  the  parts,  the  conception  of  the 
plant  as  an  organism  with  interrelated  and  interdependent 
tissues  began  to  fall  into  abeyance,  until  a  new  point 
of  view  has  within  recent  times  revivified  a  somewhat  bar- 
ren field.  This  point  of  view  is  the  physiological  one,  the 
correlation  of  structure  and  function.  Here  the  student 
of  gross  morphology  and  the  anatomist  unite  in  a  physio- 
logical interpretation  of  the  form  and  structure  of  plant 
organs,  from  which  has  grown  the  study  of  experimental 
morphology.  Advance  in  this  direction  has  been  consid- 
erable, and  we  have  now  a  much  clearer  idea  of  the  nature 
and  development  of  plant  organs;  or  at  least,  we  have  a 
much  better  attitude  in  the  interpretation  of  the  facts 
that  have  been  established  regarding  these  matters.  The 
danger  which  lies  in  this  attitude  is  the  well  known  one 
of  teleological  reasoning,  and  consequently  it  behooves  us 
to  have  some  caution  in  accepting,  without  thorough  evi- 
dence, the  interpretations  which  may  be  made  of  the  rela- 
tion of  form  and  function  and  of  special  adaptations  for 
special  purposes.  As  some  one  has  written,  "so  many 
things  may  be  true  and  so  few  things  really  are  in  the 
matter  of  use  of  special  organs,"  that  we  must  demand 
above  all  things  experimental  evidence  before  we  can 
accept  as  conclusively  proved  any  statement  as  to  function. 
It  is  permissible  to  say  without  such  proof  that  such  and 
such  an  explanation  is  plausible,  but  beyond  that  is  uncer- 
tain ground  and  mere  assertion  shows  a  temerity  at  once 
magnificent  and  pitiable.  On  the  other  hand,  it  is  ques- 
tionable if  the  extreme  attitude  of  iconoclasm  as  to  long 
established  interpretations  is  necessarily  a  wholly  reason- 
able one.  Destructive  criticism  is  not  difficult,  and  unless 
some  new  and  better  interpretation  is  suggested  the  ad- 
vance in  a  scientific  sense  is  not  considerable. 

A  further  development  from  this  physiological  attitude 
14 


is  a  branch  of  biological  work  known  as  ecology,  a  study 
of  the  relation  and  adaptation  of  single  plants  or  whole 
communities  of  plants  to  their  environment  and  to  each 
other.  It  is  the  application  in  a  broad  and  more  philo- 
sophical way  of  the  methods  of  the  physiological  anatom- 
ist coupled  with  those  of  the  taxonomist ;  but,  in  addition, 
the  work  of  the  botanist  touches  the  field  of  the  physi- 
ographer and  geologist.  Ecology  is  the  endeavor  to 
uncover  the  plan  of  nature  as  it  governs  the  relations  of 
the  different  plant  forms  in  a  given  area,  to  understand 
the  why  and  the  wherefore  of  the  association  of  very 
different  forms  in  one  locality.  The  keynote  of  the  philo- 
sophical development  of  this  topic  rests  on  the  conception 
of  the  constant  struggle  of  individuals  or  groups  of  indi- 
viduals to  maintain  themselves  against  other  forms,  which 
leads  to  a  balanced  relation  of  the  different  species  in  a 
given  flora.  Understanding  this,  we  can  see  why  if  this 
balance  is  disturbed  the  whole  fabric  of  a  plant  community 
may  be  destroyed  and  a  flora  swept  away.  We  are  also 
able  to  understand  how  relatively  slight  climatic  changes 
may  alter  completely  the  character  of  a  vegetation  in  a 
given  region,  and  thus  to  comprehend  more  readily  the 
changes  which  must  have  taken  place  in  past  ages.  It  also 
shows  us  the  effect  of  present  changes,  particularly  in  re- 
gard to  the  destruction  by  man  of  the  essential  elements 
of  natural  plant  communities,  notably  one  of  the  most 
important  of  these,  the  forests.  Its  use  lies  in  these 
directions  and  the  danger  of  its  misuse  lies  in  the  direction 
of  drawing  too  positive  conclusions  from  data  which  are 
insufficient,  and  of  accepting  the  results  obtained  as 
necessarily  final,  a  common  error  it  is  true  in  any  line 
of  thought,  but  one  to  which  the  ecologist  has  especial 
temptation. 

It  is  in  the  field  of  physiology  more  than  anywhere 
else,  perhaps,  that  the  worker  must  humble  himself  before 

15 


the  immensity  of  the  problems  before  him;  that  he  must 
realize  how  fragmentary  is  the  most  advanced  knowl- 
edge of  this  subject.  The  foundation  stone  of  physi- 
ology is  chemistry,  and  consequently  its  advance  must  go 
hand  in  hand  with  the  advance  of  that  science;  but  there 
is  also,  it  must  be  admitted,  the  element  of  empiricism, 
which  is  an  unfortunate  necessity  in  any  branch  of  learn- 
ing where  any  considerable  mass  of  facts  are  not  yet 
correlated.  The  greatest  advances  are  made  in  the  direc- 
tion of  resolving  this  empirical  information  into  more 
compact  and  definite  form,  a  task  only  possible  by  the 
accumulation  and  correlation  of  great  masses  of  data  in 
connection  with  the  more  definite  information  afforded 
by  chemistry  or  physics  and  more  particularly  modern 
physical  chemistry.  It  is  plain,  then,  that  we  can  never 
go  ahead  of  the  data  afforded  by  these  sciences,  but  must 
always  follow  somewhat  behind  them.  It  must  not  be  sup- 
posed, however,  that  physiology  is  in  a  nebulous  condition, 
despite  the  fact  that  we  are  but  on  the  margin  of  the 
unknown.  Distinct  and  creditable  advances  have  been 
made  since  the  days  when  the  knowledge  of  plant  mor- 
phology and  the  chemistry  of  Lavoisier  made  possible  any 
reasonably  satisfactory  explanation  of  the  functions  of 
plant  organs.  The  establishment  of  a  proper  understand- 
ing of  how  the  plant  obtains  its  food  has  been  a  matter  of 
the  utmost  importance,  both  from  the  development  of 
theoretical  physiology,  and  from  the  standpoint  of  prac- 
tical use.  We  know  not  only  the  definite  chemical  ele- 
ments which  are  essential  for  plant  life,  but  we  know  also 
the  quantity  and  form  in  which  they  are  most  favorable 
for  plant  growth.  Having  established  this,  it  is  possible 
to  understand  the  role  of  plants  in  the  general  economy  of 
the  world,  and  how  their  manner  of  life,  in  a  broad  sense, 
supplements  that  of  animals.  There  is  also  pretty  definite 
information  as  to  the  physical  phenomena  connected  with 

16 


the  absorption  of  the  raw  food  materials  which  the 
plant  afterwards  elaborates,  information  which  is  largely 
due  to  the  classic  researches  of  Pfeffer,  whose  work,  it 
may  be  remarked,  also  afforded  Van  t'  Hoff  valuable 
data  for  his  contributions  to  the  establishment  of  the 
modern  physical  chemistry.  Application  of  the  laws  of 
diffusion  and  of  osmosis,  as  shown  by  Pfeffer,  enables  us 
to  understand  why  a  plant  may  absorb  more  of  one  min- 
eral salt  than  of  another,  though  both  be  presented  to  it  in 
solutions  of  equal  concentration;  why  it  cannit  absorb 
some  substances  at  all,  while  on  the  other  hand  it  cannot 
avoid  absorbing  certain  substances,  even  though  they  be 
violent  poison  and  kill  the  protoplasm  of  the  absorbing 
cell  at  once.  We  understand  also  a  good  deal  of  the 
mechanism  of  the  production  from  simple  inorganic  sub- 
stances of  the  first  organic  food  by  the  green  plant,  the 
first  organic  food  of  the  whole  organic  world.  While,  as 
will  be  shown  later,  the  precise  details  of  this  process  are 
not  fully  understood,  the  general  facts  are  a  matter  of 
almost  common  information,  so  well  known  that  I  hesitate 
to  speak  of  it  here,  though  to  sum  up  the  matter  in  a  few 
words  it  may  be  said  that  this  process  of  photosynthetic 
activity  of  green  plants  is  carried  on  by  the  living  cells  in 
the  presence  of  sunlight,  through  the  agency  of  the  green 
coloring  matter — chlorophyll — which  is  present  in  the 
leaves,  and  that  the  chemical  reaction  involved  results  in 
the  union  of  the  carbon  dioxide  absorbed  from  the. air, 
with  water  absorbed  from  the  soil,  to  form  the  first  simple 
carbohydrate  that  is  to  be  detected  in  easily  recognizable 
form  as  starch.  The  fact  that  this  process  takes  place  does 
not  interfere  with  the  operation  of  another  one,  namely  the 
absorption  of  oxygen  with  the  giving  forth  of  carbon 
dioxide,  that  is  concerned  in  the  mechanism  of  respiration. 
Respiration  as  a  means  of  releasing  the  stored  energy  in 
available  form  for  the  constructive  work  of  the  organism 

17 


is  as  necessary  in  plants  as  it  is  in  animals.  These  four 
fundamental  questions,  namely,  the  inorganic  substances 
required  by  plants,  the  manner  of  their  absorption,  the 
manufacture  of  the  first  organic  food,  and  the  nature  of 
respiration  are  perhaps  the  most  important  physiological 
facts,  in  the  field  of  nutrition  at  least,  which  have  been 
definitely  established,  and  from  any  point  of  view  their 
importance  is  a  far  reaching  one. 

In  the  other  great  field  of  physiological  research,  the 
study  of  the  mechanism  of  growth  and  change  of  form, 
much  information,  made  possible  by  the  proper  under- 
standing of  the  cellular  character  of  all  living  organisms, 
has  established  many  facts  as  to  the  relation  of  plants  to 
the  great  physical  forces  which  govern  the  conditions,  the 
rate  and  the  direction  of  their  growth.  This  is  the  study 
of  the  dynamics  of  plants,  of  when  and  how  the  energy 
released  by  the  nutritive  functions  is  applied  to  the  up- 
building of  new  tissue  and  the  movement  of  plant  organs. 
Besides  the  questions  concerned  in  the  influence  of  dif- 
fusely exerted  external  factors,  there  are  also  the  effects 
produced  by  these  same  forces  when  the  stimulus  is  un- 
equal or  one-sided.  The  latter  conditions  result  in  charac- 
teristic growth  curvatures  or  tropisms,  which  continue 
until  the  plant  organ  by  its  own  action  is  brought  once 
more  into  a  state  of  equilibrium  with  the  external  forces. 
In  short,  the  various  plant  organs  are  attuned  to  the  normal 
conditions  of  equilibrium  under  which  they  grow,  and  have 
the  ability  to  perceive  and,  to  a  limited  extent,  to  transmit 
the  impulses  resulting  from  a  disturbance  of  that  equilib- 
rium. This  brings  us  to  the  question  of  the  sense  percep- 
tion of  plants,  manifested  in  a  somewhat  bizarre  fashion 
in  the  sensitive  plant,  but  we  should  go  very  slowly  in  the 
direction  of  interpreting  this  perception  in  the  same  terms 
that  we  do  that  of  higher  animals.  It  is  not  for  an  instant  to 
be  supposed  that  plants  have  any  nervous  system  such  as 

18 


is  characteristic  of  the  higher  animal  forms.  While  plants 
can  and  do  respond  to  differences  in  light  intensity  less  than 
that  which  the  human  eye  can  perceive,  it  is  gratuitous  to 
suppose  that  there  is  anything  analogous  in  the  two  pro- 
cesses. The  possibility  of  any  reasoning  action  or  instinct 
on  the  part  of  plants  is  a  question  that  the  plant  physiolo- 
gist does  not  seriously  entertain. 

In  selecting  for  discussion  present  day  problems  whifti 
may  be  considered  fundamental,  one  is  embarrassed  by  the 
wealth  of  material  and  therefore  but  one  more  or  less  con- 
nected series  of  topics  which  leads  up  to  the  modern 
mechanistic  conception  of  life  processes  has  been  chosen. 
In  doing  so  it  has  been  necessary  to  ignore  equally  import- 
ant questions  which,  though  developed  from  no  less  a 
mechanistic  standpoint,  are  more  scattered. 

In  referring  to  the  assimilation  of  carbon  dioxide  by 
green  plants  and  the  production  of  organic  food  thereby,  it 
was  necessary  to  admit  that  the  details  of  the  process  are 
not  satisfactorily  known.  It  is  evident,  however,  that  the 
starch,  which  is  the  first  substance  that  we  readily  recog- 
nize, is  not  the  first  substance  which  is  formed.  Modern 
research  points  more  and  more  to  the  conclusion  that  it  is 
the  simplest  of  carbohydrates  that  is  produced,— a  sub- 
stance known  as  formaldehyde.  But  what  is  especially 
interesting  is  that  it  seems  not  impossible  that  this  primal 
reaction  may  not  after  all  be  a  function  of  the  living  pro- 
toplasm, but  a  chemical  reaction  that  can  be  carried  on  out- 
side the  cell  through  the  agency  of  chlorophyll.  It  is  in 
the  further  elaboration  of  this  first  substance  formed  that 
the  living  protoplasm  is  apparently  necessary.  At  any 
rate  we  know  that  the  energy  demanded  for  the  process 
must  be  afforded  by  the  particular  rays  of  sunlight  which 
the  chlorophyll  absorbs. 

In  this  photosynthetic  activity  of  the  green  plant  the  car- 
bohydrate supply  of  the  world  has  been  accounted  for,  but 

19 


BIO-AGRICULTURAL  LIBRARY 
UNIVERSITY  OF  CALIFORNIA 
RIVERSIDE,  CALIFORNIA  92502 


there  is  an  equally  important  question  not  concerned  in 
this  process,  namely  the  source  for  nitrogen.  Nitrogen  is 
of  course  an  essential  element  for  the  construction  of  pro- 
toplasm. As  is  well  known  most  plants  can  utilize  it  in 
simple  combination  with  oxygen  in  the  form  of  a  nitrate, 
a  sharp  contrast,  by  the  way,  to  the  typical  animal  which 
requires  it  offered  as  an  organic  compound.  It  is  also 
known  that  the  same  plants  cannot  assimilate  the  free 
nitrogen  of  the  atmosphere,  and  further,  in  the  processes 
of  decay,  free  nitrogen  is  liberated  by  the  breaking 
down  of  the  nitrogen  compounds  in  dead  organic  matter. 
The  logical  conclusion  of  these  momentous  facts  is  that 
soon  all  the  world's  supply  of  combined  nitrogen  would 
be  exhausted, — neglecting  the  relatively  small  replenish- 
ment induced  by  cosmic  forces — so  .that  green  plants  and 
consequently  animals,  would  not  have  the  wherewithal  to 
live,  unless  there  were  some  organisms  which  could  avail 
themselves  directly  of  this  inert  gas.  Now  there  are 
plant  organisms  which  have  the  ability  to  assimilate  the 
uncombined  nitrogen  of  the  air,  certain  bacterial  forms, 
and  it  also  appears  some  somewhat  higher  plants.  But  the 
operations  that  lead  to  this  result  are  by  no  means  satis- 
factorily explained,  and  the  whole  topic  is  one  of  live 
interest  both  from  a  theoretical  as  well  as  a  practical  stand- 
point. It  should  be  added  that  from  the  latter  point  of 
view,  a  process  by  which  a  combination  of  nitrogen  with 
other  elements  in  a  form  that  is  acceptable  to  green  plants 
has  been  devised,  and  bids  fair  to  become  of  great  import- 
ance, for  combined  nitrogen  is  the  great  need  of  the  organic 
world. 

The  processes  of  nitrification  naturally  lead  us  to  the 
question  of  the  elaboration  of  nitrogen  compounds  with- 
in the  cell,  of  the  final  construction  of  proteid  material 
that  is  the  actual  food  of  the  protoplasm ;  but  here  we  are 
much  in  the  dark,  partly  because  we  have  so  little  real 

20 


information  as  to  the  chemical  structure  of  the  more  com- 
plicated nitrogenous  substances.  The  explanations  now 
given  as  to  how  this  elaboration  takes  place  are  largely 
hypothetical  and  must  be  regarded  as  quite  unsatisfactory. 

A  step  further  from  the  proteid  food  is  the  question  of 
living  protoplasm  itself,  and  one  of  the  most  interesting 
problems  connected  with  this  is  the  nature  and  functions 
of  the  enzymes,— the  ferments  and  digestive  secretiojpi 
of  living  cells.  Many  of  the  newer  theories  as  to  the  na- 
ture of  living  protoplasm  hark  back  to  investigations 
regarding  enzymes,  indeed  some  extremists  advance  the 
opinion  that  the  activities  of  the  live  protoplast  are  in 
themselves  but  the  result  of  the  interaction  of  substances 
enzymatic  in  their  nature.  There  is  no  doubt  of  the  power 
of  the  appropriate  enzymes  when  present  even  in  infini- 
tesimal amount  to  cause  enormous  molecular  changes  in 
the  substances  on  which  they  act,  but  it  is  necessary  to 
exercise  extreme  caution  before  accepting  generalizations 
along  this  line,  no  matter  how  brilliant.  The  amount  of 
empirical  information  in  this  field  is  already  becoming 
unwieldly,  and  nowhere  else  is  the  necessity  of  unifying 
principles  so  plainly  shown.  Here  it  is  that  more  definite 
chemical  knowledge  may  in  one  stroke  clear  up  the  whole 
situation. 

If  it  is  not  possible  to  ascertain  the  chemical  structure 
of  a  single  enzyme,  how  much  more  difficult  then  must  it 
be  to  determine  that  of  the  living  protoplasm?  It  goes 
without  saying,  that  if  we  try  to  analyze  the  living  proto- 
plasm, in  the  ordinary  chemical  sense,  we  kill  it.  This 
being  the  case,  the  student  who  is  trying  to  penetrate  these 
difficult  problems  must  have  recourse  to  other  modes  of 
attack.  Therefore  does  he  experiment  with  the  effect  of 
agents  which  do  not  kill  but  merely  stimulate  the  organ- 
ism or  partially  inhibit  its  functions  and,  by  studying  the 
nature  and  products  of  the  reactions  produced,  obtain 

21 


in  an  indirect  manner  clues  to  the  real  nature  of  life  pro- 
cesses. The  fascination  of  these  plunges  into  the  un- 
known is  perhaps  hardly  comprehensible  to  those  who  are 
not  engaged  in  the  work,  but  all  must  admit  the  import- 
ance of  the  end  they  have  in  view,  namely  to  penetrate  a 
little  further  into  the  mystery  of  life.  The  advance  in  all 
these  fields  is  of  necessity  along  the  line  of  the  mechanistic 
conception  of  vital  manifestations,  that  is,  the  reference 
of  them  to  chemical  and  physical  laws.  To  appeal  to  a 
"Vital  Force,"  as  my  predecessors  in  these  lectures  have 
said,  is  to  appeal  to  an  empty  name,  a  mere  "question-beg- 
ging epithet."  It  is  obvious  that  if  we  are  to  make  any 
progress  at  all,  we  must  admit  of  the  possibility  of  some 
solution  that  our  senses  can  perceive,  even  though  we  are 
perfectly  willing  to  admit  that  the  final  answer  may 
never  be  reached.  The  reference  of  vital  phenomena  to  a 
vague  "Vital  Force"  would  mean  the  extinction  of  in- 
quiry by  robbing  the  investigator  of  any  sense  of  responsi- 
bility for  adequate  explanations  of  the  results  of  his  re- 
searches. 

As  you  have  heard  in  previous  lectures,  there  is  an  in- 
creasing tendency  on  the  part  of  biologists  to  segregate  less 
sharply  the  physiological  and  morphological  fields  of 
work,  to  take  a  broader  view  of  not  only  the  content  but 
also  the  methods  of  the  two  branches  of  biological  inves- 
tigation. It  must  not  be  supposed,  however,  that  in  this 
tendency  towards  co-operation  there  is  a  return  to  omni- 
science of  the  type  of  the  old-time  naturalist,  who  by 
reason  of  the  lack  of  detail  was  able  to  consider  himself 
proficient  in  many  branches  of  science.  The  modern 
morphologist  must  still  be  a  morphologist,  and  the  physi- 
ologist a  physiologist,  only  he  has  a  broader  point  of  view 
and  does  not  hesitate  to  avail  himself  of  the  cognate 
branches  of  his  science,  or  of  any  other  science  where  he 
feels  that  he  can  further  the  aims  of  his  researches ;  he  is 

22 


an  eclectic  and  picks  that  which  will  serve  to  advance  his 
work  along  the  most  fruitful  lines. 

Almost  any  investigation  of  wide  scope  is  in  these  days 
an  example  of  this  improved  attitude,  but  no  other  per- 
haps illustrates  so  conclusively  what  may  be  called  the 
highest  type  of  modern  research  as  does  the  development  of 
the  Mutation  Theory  first  propounded  by  De  Vnes.  What 
De  Vries  has  really  done  is  to  bring  within  the  range  of 
experimental  proof  certain  questions  which  heretofore 
have  been  regarded  as  matters  of  observation  and  specula- 
tion alone.  From  this  point,  which  might  be  said  to  have 
had  its  origin  in  the  acuteness  of  observation  of  the  tax- 
onomist  and  morphologist,  the  physiological  trend  has 
ever  increased  until  the  last  word  in  this  discussion  may 
perhaps  be  for  the  physiologist  alone.  The  great  ques- 
tion involved  in  the  Mutation  Theory  is  the  old,  old  prob- 
lem of  the  origin  of  species,  a  very  considerable  advance  in 
which  has  been  made  by  De  Vries  and  those  who  were  stim- 
ulated by  his  work.  It  is  quite  wrong  to  suppose  that  he 
has  controverted  the  general  results  of  Darwin's  work;  he 
has  supplemented  it,  brought  it  within  the  range  of  more 
conclusive  proof. 

As  the  Linnaean  or  collective  species  may  be  regarded 
today  they  are  usually  separable  into  several  more  or  less 
distinct  strains  which  show  no  intergrading  forms,  and  the 
diagnosis  of  any  one  species  is,  so  to  say,  the  average  im- 
pression of  them.  To  these  distinct  strains  De  Vries  has 
given  the  name  elementary  species,  and  according  to  his 
interpretation  they  are  the  really  discrete,  finally  segrega- 
ble  units,  between  which  no  intermediate  types  exist  and 
concerning  the  origin  of  which  we  are  really  concerned. 
It  matters  not  whether  it  was  through  ignorance  or  simply 
from  convenience  that  the  earlier  taxonomists  grouped 
many  of  these  forms  into  a  single  species;  we  must  con- 
clude, that  in  general  species,  as  recognized  by  the  books, 

23 


are  quite  artificial.  It  matters  not,  also,  what  we  call 
these  finally  not  further  resolvable  forms.  Therefore  let 
us  accept  De  Vries'  terminology  and  use  the  term  elemen- 
tary species ;  the  real  point  of  the  inquiry  is  how  did  these 
forms  arise.  It  is  upon  this  that  De  Vries'  work  has 
thrown  a  great  light.  He  has  shown  that  they  may  arise 
suddenly  and  without  previous  preparation  from  pre- 
existing forms,  in  which  case  the  elementary  species  may 
be  termed  mutants,  and  the  theory  which  has  to  do  with  the 
investigation  of  their  origin  the  Mutation  Theory. 

The  next  task  then  is  to  examine  more  closely  the 
methods  which  De  Vries  employed,  the  evidence  which  he 
has  to  support  his  views,  both  as  to  the  observations  on 
the  origin  of  these  mutants  and  their  behavior  after  they 
have  come  into  being,  and  further,  what  success  subsequent 
investigators  have  had  in  supporting  De  Vries'  evidence, 
and  how  far  they  have  extended  his  conclusions.  In  the 
first  place,  it  may  be  remarked  that  the  conclusions  as  first 
published  in  1901  and  1902  were  not  the  outcome  of  any 
hasty  experiments  and  ill  digested  data,  but  were  the  re- 
sult of  seventeen  years  of  the  most  careful  and  painstak- 
ing work,  and  a  fine  example  of  the  best  kind  of  quiet, 
faithful  research,  removed  from  the  rush  of  affairs  and  the 
demand  for  immediate  results,  the  final  conclusion  of 
which  fully  warranted  the  time  and  labor  expended. 

As  is  well  known,  Professor  de  Vries  found  in  La- 
marck's evening  primrose— Oenothera  Lamarckiana— 
a  plant  most  favorable  for  observation,  though  his  conclu- 
sions are  not  based  on  that  form  alone.  The  most  care- 
fully guarded  pedigree  cultures  were  made  from  the  true 
Lamarckiana  type,  and  the  astonishing  result  developed 
that  among  the  offspring  of  these  certain  forms,  to  the 
number  of  about  four  per  cent,  showed  new  and  striking 
differences.  In  all,  more  than  a  dozen  new  forms  were  ob- 
tained which,  if  they  could  be  bred  at  all,  bred  true  to  their 

24 


new  characters  and  did  not  revert  to  the  ancestral  Lamarck- 
iana;  these  were  the  mutants,  the  new  elementary  species, 
which  had  sprung  suddenly  in  a  saltatory  fashion  from  the 
parent  stock.  The  great  importance  lies  in  the  fact  that 
they  were  entirely  constant  to  their  new  characters,  and 
were  thus  not  in  the  class  of  the  merely  unstabjg  varieties. 
It  must  be  remarked  that  time  alone,  many  generations, 
of  carefully  guarded  cultures  in  which  accidental  cross- 
ing was  an  impossibility,  together  with  unimpeach- 
able records,  could  adequately  establish  this  momentous 
fact,  that  here  was  a  new  species,  a  new  form,  or  what- 
ever you  may  elect  to  call  it,  which  had  sprung  all  in  one 
jump  from  its  parental  stock.  De  Vries,  then,  was  the  first 
man  who  ever  saw  a  new  type  of  organism  come  into  the 
world  and  who  recorded  its  advent. 

You  naturally  ask  how  unlike  were  these  new  forms,  a 
question  which  is  difficult  to  answer  without  actual  illus- 
trations. However,  it  may  be  said  that  many  of  them 
were  different  enough  from  their  parent  stock  to  be  ad- 
mitted by  taxonomists  to  come  within  the  definition  of 
new  species,  as  species  are  regarded  at  the  present  time. 
The  differences  are  not  the  question  of  mere  stature,  but 
of  the  whole  habit  of  the  plant  and  of  the  details  of 
the  form  of  both  leaves  and  flowers.  But  to  repeat, 
it  really  makes  no  odds  whether  the  differences  are 
of  such  quality  that  they  must  needs  be  recognized  as 
specific  by  taxonomists ;  what  is  important  is  that  they  are 
differences  which  do  not  intergrade  one  with  another  and 
which  are  inheritable  in  the  second,  third  and  subsequent 
generations,  and  that  no  tendency  to  revert  to  the  parent 
form  is  to  be  observed. 

The  results  of  De  Vries  have  been  verified  by  cultures  in 
this  country  of  his  own  and  of  other  stock,  so  that  there 
can  be  no  question  that  this  Lamarck's  evening  primrose 
behaves  in  its  manner  of  mutation  the  same  here  as  else- 

25 


where.  More  thin  that,  other  mutating  forms  have  been 
discovered,  and  by  the  application  of  biometric  methods 
much  that  is  important  regarding  the  relative  variability 
of  mutants  and  their  parent  stock  has  been  determined.  Be- 
sides the  actual  experimental  work,  the  history  of  Lamarck's 
evening  primrose  has  been  traced  back  for  more  than  a 
century  and  a  mass  of  inferential  data  is  being  accumu- 
lated which  helps  to  support  the  main  conclusions.  Im- 
portant as  all  these  advances  are,  the  most  brilliant  result 
is  that  obtained  along  the  lines  of  the  induction  of  muta- 
tions. By  the  injection  into  the  developing  ovary  of  a 
plant  allied  to  Lamarck's  evening  primrose  of  reagents 
which  might  produce  a  chemical  or  osmotic  effect  upon 
the  cell  contents,  MacDougal  has  actually  succeeded  in 
inducing  mutations.  The  seed  grown  from  the  stimulated 
plant  may  produce  forms  quite  distinct  from  the  parent 
type  and,  what  is  essential,  the  mutations  thus  induced  are 
constant  to  the  second  and  third  generations.  That  such 
a  result  can  be  obtained  is  simply  astounding  when  one 
considers  how  firmly  bound  an  organism  is  by  its  heredity. 
It  would  appear  that  a  tremendous  shock  had  been  given 
the  plant  at  a  critical  period  in  its  life  history  which  has 
enabled  or  forced  it  to  break  down  some  of  the  minor 
barriers  imposed  by  its  hereditary  tendencies  and  to  erect 
new  ones,  which  circumscribe  its  offspring  as  the  original 
ones  did  its  parent.  As  to  the  precise  nature  of  this  shock 
we  can  at  present  only  speculate,  but  it  is  permissible  to 
suggest  that  it  is  perhaps  of  the  nature  of  the  rearrange- 
ment, in  a  chemical  sense,  of  the  protoplasm  of  the  cells  of 
the  sexual  generation.  As  to  the  natural  production  of 
mutants,  given  such  a  conception  of  the  nature  of  the  pro- 
cess involved,  it  is  possible  to  suggest  various  ways  in 
which  it  might  have  been  brought  about. 

The  line  of  departure  of  mutants  from  the  parent  type 
is  not  in  any  one  direction,  and  the  manner  of  variation 

26 


appears  to  be  wholly  a  matter  of  what  we  are  pleased  to 
call  chance.  As  has  been  said,  De  Vries  obtained  more 
than  a  dozen  different  forms.  Some  of  the  mutants,  we 
may  say,  are  probably  destined  to  failure,  others  perhaps 
are  better  placed,  at  least  in  new  environment,  than  the 
parental  type  and  might  conceivably  stamp  rt  out  in  time. 
What  the  criteria  of  success  or  non-success  may  be  is  a 
matter  upon  which  no  one  would  care  to  give  an  opinion, 
but  I  have  in  mind  the  fact  that  one  of  the  mutants  of 
Lamarck's  evening  primrose  has  a  tendency  to  germi- 
nate somewhat  more  quickly  than  the  parent  form,  and 
the  seedling  grows  a  little  more  rapidly;  it  is  conceivable 
that  some  slight  advantage  of  this  sort  might  be  the  cru- 
cial point.  However  that  may  be,  it  is  here  that  we  can 
apply  the  Darwinian  concept  of  the  struggle  for  exist- 
ence, a  struggle  however  not  between  single  individuals, 
as  the  idea  of  continuous  variation  would  imply,  but  the 
struggle  between  great  numbers  of  individuals,  whole 
groups  of  elementary  species.  The  great  contrast  be- 
tween Darwin  and  De  Vries  is  the  contrast  between  the 
slow  and  continuous  accretion  of  variations  implied  by  the 
former  and  the  sudden  jumping  or  saltatory  variation  in- 
sisted on  by  the  latter.  By  such  means  as  De  Vries  main- 
tains the  process  of  evolution  might  take  place  with  far 
greater  rapidity  than  by  Darwin's  method,  for,  generous 
as  the  geologists  are  in  their  allowance  of  time  for  the 
development  of  organic  life  on  the  world,  it  has  always 
been  difficult  of  conception  how  even  the  countless  ages 
granted  could  compass  the  enormous  development  of  the 
highest  organic  types  from  simple  forms.  To  maintain 
that  De  Vries'  theory  is  entirely  complete,  and  must  be 
the  only  means  of  the  origin  of  new  forms,  is  unneces- 
*sary.  None  but  the  extremist  would  go  to  such  a 
length;  it  is  not  at  all  necessary  to  assume  that  the 
means  to  a  similar  end  must  necessarily  be  similar. 

27 


What  may  be  maintained,  and  properly  so,  is  that  muta- 
tion constitutes  one  way,  at  least,  by  which  new  forms 
of  organisms  may  arise  on  the  world's  surface.  New 
forms,  in  the  sense  of  the  new  combinations  of  old  charac- 
ters which  come  into  being  by  reason  of  stable,  non-re- 
verting hybrids,  are  known  to  have  originated,  but  such 
new  forms  imply  of  course  the  pre-existence  of  varied 
types,  and  do  not  have  to  do  with  the  Question  of  the 
origin  of  new  characters. 

It  is  not  in  the  order  of  things  that  a  new  theory  of  such 
import  as  the  Mutation  Theory  should  not  find  oppo- 
nents. These  I  think  may,  in  the  main,  be  grouped  in 
three  classes.  First,  the  critics  who  doubt  the  evidence, 

I 

who  can  be  answered  by  referring  them  to  the  printed 
records,  and  recommending  a  repetition,  as  careful  as  the 
original  work,  of  the  experiments  which  have  led  to  the 
new  point  of  view.  Second,  those  who  quibble  concern- 
ing terms,  and  this  type  I  think  constitutes  the  majority, 
who  will  likely  suffer  the  fate  that  is  usually  meted  out  to 
quibblers,  that  of  being  ignored.  Lastly,  those  opponents 
who,  while  they  may  not  doubt  the  accuracy  of  the  work, 
doubt  the  conclusions  on  philosophical  grounds.  These 
are  the  critics  whom  the  advocate  of  the  De  Vries  Theory 
must  welcome  and  who  will  arrest  his  sober  attention,  for 
they  will  stimulate  him  to  accumulate  more  and  more  evi- 
dence to  support  his  position.  Even  were  I  able  to  analyze 
adequately  the  controversial  side  of  the  question  for  you, 
it  is  obvious  that  time  scarcely  allows,  and  I  will,  in  conse- 
quence, state  frankly  that  the  account  which  I  have  pre- 
sented is  from  the  standpoint  of  an  advocate  of  what  the 
Mutation  Theory  teaches,  and  add  that  I  am  not  aware 
that  any  experimental  work  has  controverted  it.  Let  me 
say,  however,  and  here  I  wish  to  speak  for  myself  alone, 
that  I  cannot  see  it  makes  great  odds  whether  fifty  years 
hence  or  five  years  hence  we  accept  the  Mutation  Theory 

28 


just  as  propounded  by  De  Vries.  The  great  point  is  that 
an  advance  has  been  made,  the  most  important  advance 
since  the  time  of  Darwin,  by  way  of  helping  to  elucidate 
one  of  the  great  questions  in  which  man  is  interested.  It 
is  not  to  be  supposed  that  we  have  as  yet  any  final  answer 
to  this  question,  final  answers  are  not  indeed  the  goal  of 
any  one  scientific  research.  It  was  Sir  Isaac  Newton,  I 
think,  who  said  that  the  seeker  after  ultimate  causes  did 
not  show  the  true  scientific  spirit,  and  he  was  right.  What 
we  have  is  one  of  the  proximate  causes  demonstrated  to  a 
degree  which  had  not  been  previously  attained.  A  scien- 
tific theory  is  like  an  organism,  it  grows  and  it  may  also 
propagate  itself,  and  all  the  theories  of  evolution  from 
Lamarck  to  De  Vries,  and  those  that  will  follow,  will 
themselves  be  an  example,  as  it  were,  of  the  principle  that 
they  teach.  A  theory  starts  life  an  intellectual  pigmy, 
may  develop,  if  it  have  the  vitality,  into  a  veritable  intel- 
lectual colossus,  and,  after  it  has  run  its  course,  may  leave 
behind  its  offspring.  It  is  not  a  cause  of  reproach  but 
rather  of  congratulation  that  the  scientific  theory  of  today 
may  be  discarded  tomorrow,  for  no  theory  wrill  be  aban- 
doned until  a  better  one  has  been  brought  forward  to  take 
its  place,  one  which  can  explain  the  facts  in  a  way  more 
satisfying  to  the  human  mind.  Change  in  such  a  case  is 
progress,  and  since  science  must  of  necessity  be  always 
progressing  so  also  must  it  be  always  changing. 

To  those  who  are  conversant  with  the  problems  con- 
nected with  the  origin  of  species  it  must  be  obvious  that 
this  consideration  of  the  subject  does  not  cover  the  whole 
ground;  so  obvious  indeed  that  perhaps  it  is  unnecessary 
for  me  to  remark  that  it  is  not  intended  to.  There  are 
other  theories  to  be  considered  and  other  equally  import- 
ant matters  that  are  more  or  less  interwoven  with  any  one 
theory  of  the  evolution  of  new  forms.  Thus  no  reference 
has  been  made  to  Mendel's  researches  on  heredity,  or 

29 


the  way  in  which  they  touch  upon  the  De  Vries  Theory. 
This  has  been  omitted  purposely,  for  while  the  results  of 
Mendel's  original  experiments  in  the  breeding  of  peas 
might  be  cited  at  length,  I  doubt  if  an  apter  or  more 
significant  example  could  be  found  than  the  one  which 
Professor  Wilson  used,  and  as  Professor  Wilson  himself 
said,  the  explanation  while  not  abstruse  is  one  that  requires 
considerable  preparatory  consideration.  The  Mutation 
Theory  has  been  developed  more  in  detail,  as  representing 
a  type  of  research.  Being  one  of  the  latest  and  most  im- 
portant contributions  to  biological  science,  and  being  also 
entirely  germane  to  the  subject  in  hand,  it  has  seemed 
proper  to  devote  some  time  to  its  consideration.  At  many 
points  do  the  fields  of  modern  botany  and  modern  zo- 
ology touch,  but  perhaps  it  is  nowhere  so  evident  as  in 
great  problems  like  these.  Here  the  two  sciences  work  in 
generous  rivalry,  each  eager  to  add  its  contribution  to  the 
store  of  general  knowledge,  to  utilize  such  information  as 
the  sister  science  brings,  to  criticize  it  if  need  be,  but 
always  to  accord  it  a  respectful  hearing 

So  much  then  for  the  purely  theoretical  side  of  botani- 
cal research  of  which  I  have  presented  a  hasty  glimpse.  It 
is  necessary  before  closing  to  make  some  reference  to  the 
utilitarian  aspect;  where  and  how  botany  directly  serves 
the  material  needs  of  man.  I  hold  it  myself  to  be  a  matter 
of  some  pride  that  a  science  like  botany  with  a  side  so 
purely  theoretical  and  impractical  can  also  lend  itself  to 
further,  in  such  important  ways  as  it  does,  the  well-being 
of  mankind,  for  in  the  direct  application  of  botanical  in- 
formation to  agricultural  questions  the  ways  and  means 
of  life  may  be  ameliorated.  Moreover,  it  is  some  of  the 
most  theoretical  and  recondite  researches  which  have  led 
to  the  most  important  practical  results. 

It  is  possible  to  consider  only  a  few  phases  of  the  prac- 
tical application  of  botany,  and  I  will  choose  those  which 

30 


are  not  commonly  recognized,  and  which  require  a  high 
degree  of  special  botanical  training.  The  necessity  of 
botanical  knowledge  in  the  use  of  plants  and  their  prod- 
ucts in  the  arts,  or  as  drugs,  is  easily  understood  without 
further  reference,  and  such  uses  do  not  necessarily  involve 
any  broad  knowledge  of  plants  as  a  whole. 

It  is  quite  different,  however,  in  the  matter  of  plant 
pathology,  for  here  every  channel  of  botanical  informa- 
tion must  be  used  to  investigate  plant  ailments.  Bacteria 
and  parasitic  fungi,  which  are  themselves  plants  of  a  low 
order,  are  the  cause  of  the  bulk  of  plant  diseases  and  for 
that  reason  the  study  of  their  life  histories  becomes  a  mat- 
ter of  no  small  importance.  Then,  too,  the  structure  and 
habits  of  the  host  plants  must  be  taken  into  consideration, 
for  upon  these  may  depend  the  means  of  prevention  or  of 
cure.  The  assembling  of  this  information  and  its  prac- 
tical application  to  the  question  in  hand  devolve  upon  that 
type  of  botanist  usually  referred  to  as  the  mycologist, 
and  despite  many  failures  much  that  is  of  substantial 
practical  use  has  been  established.  One  of  the  earliest,  if 
not  the  earliest,  recorded  instances  of  where  a  community 
has  taken  formal  notice  of  the  fungus  pests  of  plants  is 
found  in  the  old  Barberry  Law  passed  by  the  province 
of  Massachusetts  before  the  Revolution.  This  called  for 
the  extirpation  of  the  barberry  which  had  been  noticed  by 
the  colonists,  without  any  knowledge  on  their  part  of  the 
real  cause,  to  be  connected  with  the  rust  of  their  wheat 
fields.  Today  we  may  not  pass  laws  for  the  destruction 
of  diseased  plants,  realizing  perhaps  the  hopelessness  of 
enforcing  them,  but  we  combat  plant  disease  by  the  estab- 
lishment of  experiment  stations  devoted  to  the  investiga- 
tion of  such  matters. 

As  a  result,  there  is  now  at  the  disposal  of  the  agricul- 
turalist much  definite  information  of  ways  and  means  of 
diminishing  or  preventing  loss  through  the  destruction  of 

31 


crops  by  disease,  losses  which  statistics  show  may  amount 
to  tens  of  millions  annually;  and  while  the  study  of  the 
action  of  bacteria  and  fungi  in  the  disease  of  plants  is  by 
no  means  complete,  no  one  can  deny  the  practical  results 
which  have  been  attained.  In  the  more  indefinite  func- 
tional diseases  of  plants  not  ascribable  to  definite  parasites, 
there  is  room  for  much  more  information,  which  will  be 
forthcoming  when  our  knowledge  of  nutrition  physiology 
is  more  full.  Already,  however,  we  have  suggestions  as 
to  the  cause  of  the  functional  diseases  which  often  appear 
where  the  same  crop  has  been  raised  for  many  years  in 
succession  in  the  same  spot,  which  bid  fair  to  explain  some 
important  plant  ailments  that  are  at  present  not  under- 
stood. 

A  more  popularly  interesting  line  of  activity  that  has  a 
practical  bearing  is  found  in  plant  breeding,  which  has 
recently  been  attracting  wide  attention.  Plants  are  now 
bred  systematically  for  desired  characters,  not  always 
simply  for  increased  yield,  but  also  for  such  qualities  as 
resistance  to  extremes  of  temperature,  to  lack  of  moisture 
in  dry  or  semi-arid  regions,  to  resistance  towards  specific 
diseases,  and  even  for  the  more  esthetic  qualities  of  flavor 
or  color.  The  old  hit  or  miss  methods  of  the  improvement 
of  strains  by  empirical  rules  of  selection  is  passing  away, 
and  more  and  more  scientific  methods,  based  on  the  latest 
results  of  investigations  of  heredity  and  variation,  are 
being  employed.  Passing  over  the  older  methods  I  will 
take  up  two  very  different  types  of  plant  breeding,  both 
modern:  one  the  strictly  scientific,  the  other  the  intuitive. 

The  first  method  we  owe  largely  to  Nilsson,  who  intro- 
duced it  at  an  experiment  station  in  Sweden  in  connection 
with  the  cultivation  of  various  cereal  crops.  It  may  be 
said  that  previous  to  his  advent  the  older  methods  had 
been  tried  and  abandoned  as  a  failure.  With  his  knowl- 
edge of  what  had  been  published  about  heredity  and 

32 


variation,  Nilsson,  after  some  preliminary  experiments, 
arrived  at  the  conclusion  that  no  new,  pure  or  constant 
strains  of  wheat  could  be  obtained  unless  the  fruit  of  a 
single  ear  was  bred  separately,  and  thus  he  established 
what  is  known  as  the  principle  of  breeding  from  the  single 
ear  and  not  from  assorted  lots  of  seed  taken  from  many 
individuals.  This  breeding  he  continued,  picking  out  any 
chance  favorable  ear  which  he  could  find,  until  he  obtained 
many  thousands  of  different  forms  owing  to  this  multi- 
plicity of  strains  mixed  in  the  ordinary  wheat.  Of  course 
some  turned  out  to  be  mere  bastard  strains  and  only  the 
ones  which  continued  to  breed  true  to  character  were  kept. 
These  constituted  the  new  agricultural  varieties,— in  real- 
ity elementary  species  and  mutants — which,  after  severe 
tests  had  proved  them  suitable,  were  raised  in  marketable 
quantity  for  seed.  The  amount  of  work  involved  was 
enormous,  the  mere  bookkeeping  of  the  accurate  pedigree 
record  with  notes  on  the  life  history  of  each  form  and  its 
progeny  was  in  itself  no  small  matter.  Besides  the  prin- 
ciple of  single-ear  breeding,  Nilsson  also  established  the 
fact  that  but  a  single  selection  alone  is  necessary  to  fix 
a  new  strain,  provided  the  progeny  of  the  chosen  ear  are 
carefully  guarded  from  admixture  with  other  forms.  All 
this  seems  absurdly  simple,  and  it  is  simple,  so  much  so 
that  it  is  quite  possible  of  application  by  a  person  of  aver- 
age intelligence  who  has  had  the  proper  instruction,  but 
the  important  point  is  that  it  was  discovered  by  the  appli- 
cation of  thoroughly  scientific  methods.  Nilsson's  princi- 
ple is  in  very  general  application  today  and  is  being  used 
to  excellent  effect  in  the  improvement  of  Indian  corn  in 
the  middle  West. 

Contrast  with  this  the  methods  of  Mr.  Burbank,  whose 
name  is  familiar  to  all.  It  is  not  that  he  should  not  be 
given  the  credit  of  having  established  new  and  useful 
strains  of  cultivated  plants,  or  of  having  done  some 

33 


remarkable  feats  in  the  way  of  plant  breeding;  but  it  is 
that  his  methods  are  almost  purely  intuitive  and  would  die 
with  him,  were  his  own  records  all  that  there  was  to  be  left 
behind,  a  striking  difference  from  the  mass  of  data  accu- 
mulated by  Nilsson.  It  is  the  rule  of  thumb  method, 
picturesque  but  uncertain,  as  against  the  surer  but  less 
romantic  practices  of  science. 

The  matter  of  general  scientific  agriculture  opens  an 
immense  field  in  which  I  can  call  your  attention  to  a  few 
points  only.  The  scientific  care  of  our  forests,  for  trees 
may  be  regarded  as  a  crop  and  their  culture  agriculture, 
is  a  question  to  which  we  in  this  country  are  awakening 
none  too  soon.  Forestry  as  practised  in  Europe,  demand- 
ing as  it  does  expert  botanical  knowledge,  perhaps  not  by 
the  foresters  themselves  but  by  those  who  direct  their 
labors,  has  saved  what  were  the  fast  diminishing  wooded 
areas.  There  is  need  of  haste  with  us  for  similar  scientific 
treatment  of  the  problem  by  men  who  are  not  simply 
woodsmen,  but  botanists  as  well. 

Thr  scientific  rotation  of  crops,  the  use  of  fertilizers 
and  the  study  of  the  physical  and  chemical  condition  of 
the  soil  in  connection  with  the  living  plants,  involve  ques- 
tions which  may  mean  the  success  or  failure  of  much  of 
our  farming.  These  questions  can  only  be  settled  by  care- 
ful investigations  which  take  into  consideration  the  nature 
of  the  plants  themselves  as  well  as  the  physical  conditions 
of  their  environment.  Some  may  say  that  knowledge 
along  this  line  has  been  satisfactorily  handed  down  from 
father  to  son,  that  the  farmer  knows  his  business  better 
than  does  the  scientist,  but  it  is  a  patent  fact  that  this  is 
not  so.  For  instance,  many  a  farm  which  has  been  dam- 
aged for  a  long  period  of  years  by  the  over-liming  of  the 
soil  might  have  been  spared  had  the  farmer  of  fifty  years 
ago  had  the  knowledge,  which  we  now  have,  of  the  relation 
of  lime  to  the  other  mineral  substances  needed  by  the 

34 


plant,  of  when  to  apply  it  and  when  to  withhold  it.  It  is 
the  difference  between  merely  empirical  knowledge  and 
that  which  is  based  on  scientific  principles. 

When  the  contest  comes  between  virgin  soil  and  long 
tilled  land,  the  latter,  no  matter  how  rich  it  may  once  have 
been,  must  needs  be  cultivated  more  intensively  if  it  is  to 
hold  its  own.  Intensive  cultivation  requires  the  aid  of 
special  information  and  it  is  here  that  scientific  agricul- 
ture comes  into  play.  Few  people  realize  that,  without 
artificial  fertilizers,  the  direct  outcome  of  highly  theoretical 
work  on  the  raw  food  stuffs  of  plants,  much  of  the  farm- 
ing of  today  would  be  almost  impossible.  And  the  proper 
use  of  fertilizers  is  but  one  of  many  questions. 

We  are  coming  now  in  this  country  to  a  stage  in  its 
development  when  scientific  agriculture  must  be  seriously 
considered.  Fortunately  it  is  being  so  considered  and 
the  federal  and  state  establishments  devoted  to  the  inves- 
tigation of  these  agricultural  questions  may  confidently 
be  expected,  I  think,  to  help  in  the  solving  of  the  practical 
economic  questions  that  must  arise  in  the  competition  of 
our  own  agriculture  with  that  of  other  lands.  The  way  it 
must  be  done  is  by  the  introduction  of  improved  methods 
based  on  carefully  conducted  scientific  research,  that 
often  find  their  stimulus  in  the  highly  theoretical  investi- 
gations of  the  pure  scientist.  Thus  must  the  so-called 
impractical  devotee  of  science  come  in  contact  with  the 
practical  man  of  affairs  and  furnish  him  knowledge  that 
can  be  used  for  the  benefit  of  all. 

In  this  somewhat  categorical  fashion  then,  I  have  en- 
deavored to  present  to  you  some  of  the  content  of  the 
science  of  botany;  that  science  which  consists  of  the  dis- 
membering of  flowers  and  the  giving  to  them  of  long 
names.  What  its  future  will  be  is  perhaps  already  indi- 
cated, but  briefly  you  can  see  that  it  is  the  direction 
of  physiological  advance,  away  from  pure  taxonomy  and 

35 


formal  morphological  conceptions  towards  the  realm  of 
function;  away,  too,  from  any  segregation  of  the  science 
from  kindred  fields  towards  a  better  understanding  of  the 
place  of  plants  in  the  whole  cosmic  scheme. 

Man's  attitude  towards  the  unknown,— his  philosophy 
in  short — must  influence  his  attitude  towards  botany  as  it 
will  towards  any  science ;  and  since  philosophy,  like  other 
lines  of  intellectual  activity,  changes  and  progresses, 
man's  attitude  towards  science  is  not  a  fixed  or  rigid  one. 
But  it  is  not  likely  that  philosophy  will  ever  tend  to  dis- 
courage investigation,  and  investigation  is  the  keynote  of 
scientific  progress.  Unquestionably,  the  world  demands 
research,  and  any  fact  no  matter  how  humble,  if  accu- 
rately established,  helps  on  the  cause.  Perhaps  the  time 
will  come  when  our  knowledge  of  today  will  seem  as  crude 
as  that  of  yesterday  now  seems  to  us.  Let  not  that  con- 
cern us,  except  to  urge  us  to  do  what  we  may  in  hastening 
this  time,  knowing  that  that  is  where  real  progress  lies, 
and  knowing  too  that  there  is  ample  work  that  can  and 
must  be  done. 


36 


COLUMBIA  UNIVERSITY  PRESS 


A   SERIES  of  twenty-two  lectures  descriptive  in  untechnical  language  of 
the  achievements  in   Science,   Philosophy  and  Art,  and  indicating  the 
present  status  of  these  subjects  as  concepts  of  human  knowledge,  are  being 
delivered  at  Columbia  University,   during  the  academic  year   1907-1908,  by 
various  professors  chosen  to  represent  the  several  departments  of  instruction. 

MATHEMATICS,  by  Cassius  Jackson  Keyser,  Adrain  Professor  of  Mathe- 
matics. 

PHYSICS,  by  Ernest  Fox  Nichols,  Professor  of  Experimental  Physics. 

CHEMISTRY,  by  Charles  F.  Chandler,  Professor  of  Chemistry. 

ASTRONOMY,  by  Harold  Jacoby,  Rutherfurd  Professor  of  Astronomy. 

GEOLOGY,  by  James  Furman  Kemp,  Professor  of  Geology. 

BIOLOGY,  by  Edmund  B.  Wilson,  Professor  of  Zoology. 

PHYSIOLOGY,  by  Frederic  S.  Lee,  Professor  of  Physiology. 

BOTANY,  by  Herbert  Maule  Richards,  Professor  of  Botany. 

ZOOLOGY,  by  Henry  E.  Crampton,  Professor  of  Zoology. 

ANTHROPOLOGY,  by  Franz  Boas,  Professor  of  Anthropology. 

ARCHAEOLOGY,  by  James  Rignall  Wheeler,  Professor  of  Greek  Archae- 
ology and  Art. 

HISTORY,  by  James  Harvey  Robinson,  Professor  of  History. 

ECONOMICS,  by  Henry  Rogers  Seager,  Professor  of  Political  Economy. 

POLITICS,  by  Charles  A.  Beard,  Adjunct  Professor  of  Politics. 

JURISPRUDENCE,  by  Munroe  Smith,  Professor  of  Roman  Law  and 
Comparative  Jurisprudence. 

SOCIOLOGY,  by  Franklin  Henry  Giddings,  Professor  of  Sociology. 

PHILOSOPHY,  by  Nicholas  Murray  Butler,  President  of  the  University. 

PSYCHOLOGY,  by  Robert  S.  Woodworth,  Adjunct  Professor  of  Psy- 
chology. 

METAPHYSICS,  by  Frederick  J.  E.  Woodbridge,  Johnsonian  Professor  of 
Philosophy. 

ETHIC?,  ^  J0hn  Dewey,  Professor  of  Philosophy. 

PHJLOLOGY,   by   A.    V.    W.   Jackson,   Professor   of   Indo-Iraman   Lan- 

LITERATURE,  by  Harry  Thurston  Peck,  Anthon  Professor  of  the  Latin 
Language  and  Literature. 

These  lectures  are  published  by  the  Columbia  University  Press  separately  in 
pamphlet  form,  at  the  uniform  price  of  twenty-five  cents  carnage  extra. 
Orders  will  be  taken  for  the  separate  pamphlets,  or  for  the  who 

Address 

THE  COLUMBIA  UNIVERSITY  PRESS 

Columbia  University,  New  York 


DATE  DUE 


OEMCO  38-297 


QK81 

R52 

1908 


Richards,  Herbert  Maule 

Botany  [a  lecture  delivered 
at  Columbia  University  in 
the  series  on  science, 
philosophy  and  art, 
December  4,  1907] 


LIBRARY  FACILITY 


A 000642549 


BIO-AGRICULTURAL  LIBRARY 
UNIVERSITY  OF  CALIFORNIA 
RIVERSIDE,  CALIFORNIA  92502 


